Tuesday, September 10, 2013

Pacific Sea Surface Temperatures Warming; Is an El Nino Winter Ahead?

Sea surface temperature anomalies across all four ENSO regions in the Pacific are warming in what could be a sign of the La Nina-like SST's we saw earlier this year breaking down.

A swath of above normal temperature values roughly 50 to 200 meters underwater is beginning to push towards the surface and strengthen. The swath has been present underwater for some time now; it's possible we could see further warming in weeks ahead. The CFS v2 makes a case for this idea, showing continuous warming in the main ENSO region (3.4) for the next few months. I'm not really keen on getting in with this warming idea- the CFS has proven itself wrong before with warming SST's across the Pacific, and the rapid warming the model is showing in weeks ahead may not verify.

On the chance this rapid warming does occur, the question becomes: Will we see an El Nino for this winter?

If we see the SST's warm enough, then yes, we would see an El Nino. There are numerous caveats with the premise of an El Nino this winter, but I've already explained a few of them above. What we really care about is- would this El Nino transfer into the atmosphere? Based on current projections, I would not think so. Current model forecasts and analog years suggest a cooler than normal upper US, whereas an El Nino would bring about a warm trend throughout the Plains and Midwest.

Time will tell if we actually see an El Nino develop, but right now, I am skeptical of the idea.